The present invention is directed to glassware forming systems that form articles of glassware from individual molten glass gobs, and more particularly to a method and apparatus for cooling the deflectors that direct the molten glass gobs into the blank molds at each section of an individual section glassware forming machine.
The art of manufacturing articles of glassware, such as glass containers, is currently served by the so-called individual section machine. Such a machine includes a plurality of separate or individual manufacturing sections, each of which has a multiplicity of operating mechanisms for converting one or more charges or gobs of molten glass into articles of glassware such as hollow glass containers, and for transferring the containers through the successive stages of the machine section. In general, an individual section glassware forming machine system includes a glass source with a needle mechanism for controlling one or more streams of molten glass, a shear mechanism for cutting the molten glass into individual gobs, and a gob distributor for distributing the individual gobs among the individual machine section. Each machine section includes one or more blank molds and one or more associated deflectors for receiving the gobs and redirecting the gobs to fall by gravity into the associated blank molds, within which each gob is initially formed in a blowing or pressing operation. One or more invert arms transfer the blanks to blow molds in which the articles are blown to final form, tongs remove the formed articles onto a deadplate, and a sweepout mechanism transfers molded glass articles from the deadplate onto a machine conveyor. The conveyor receives containers from all sections of the individual section machine, and conveys the containers to a loader for transfer to an annealing lehr. Operating mechanisms in each section also provide for closure of mold halves, movement of baffles and blow nozzles, control of cooling wind, etc. U.S. Pat. No. 4,362,544 provides a background discussion of the art of both xe2x80x9cblow and blowxe2x80x9d and xe2x80x9cpress and blowxe2x80x9d glassware forming processes, and discloses an electropneumatic individual section machine adapted for use in either process.
The loading of molten glass gobs into the blank molds of the individual machine sections is a critical stage of system operation. The gob shear mechanism and gob distributor are disposed in fixed position above an individual section machine, and the molten glass gobs are fed by gravity through chutes and troughs to the individual machine sections. The distance of travel of the molten glass gobs to the individual machine sections varies substantially depending upon spacing between the machine sections and the gob distributor. Thus, temperature of the molten glass gobs fed to the blank molds can vary significantly among the machine sections, and indeed among the blank molds of each machine section. Timing of molten glass delivery can also be affected by temperatures of the several paths in the gob distribution system. It is a general object of the present invention to provide a method and apparatus for improving uniformity of gob loading into the blank molds of the several machine sections, and thereby improving the quality and productivity of the overall glassware forming system.
A glassware forming machine system in accordance with a presently preferred embodiment of the invention includes an individual section glassware forming machine having a plurality of sections, each with at least one blank mold, and a gob distributor for distributing molten glass gobs to the blank molds of each machine section in sequence. The molten glass gobs are delivered to the blank molds of each section through channels on which the glass gobs slide to each blank mold. At least one liquid coolant passage is integral with each channel, and the several coolant passages for the entire machine are connected in parallel between source and return liquid coolant manifolds. Variable flow control valves are individually connected between each liquid coolant passage and the return manifold for controlling flow of liquid coolant through the passages and thereby balancing temperatures among the parallel gob channels. In this way, all of the gob flow channels are maintained at the same temperature, which improves uniformity of temperature and timing of gob delivery to the blank molds of the several machine sections regardless of distance between the gob distributor and the machine sections.
In the preferred embodiment of the invention, the several gob delivery channels include gob deflectors disposed in fixed positions adjacent to the blank molds of each machine section for deflecting molten glass gobs into the blank molds. Each such deflector has an associated integral liquid coolant passage. An automatic or manual flow control valve is connected between each deflector coolant passage and the coolant return manifold. Temperature or pressure of liquid coolant is monitored between each deflector coolant passage and the return manifold is monitored, and each automatic or manual valve is controlled so as to maintain constant coolant flow and/or temperature among the several deflectors.
In accordance with another aspect of the present invention, a method of equalizing temperatures among molten glass gobs fed through deflectors to the blank molds at each section of an individual section glassware forming machine contemplates providing a liquid coolant flow passage integral with each deflector, directing liquid coolant through the passages in parallel to draw heat from the deflectors, and controlling coolant flow to maintain the deflectors at identical temperatures. The last step preferably is carried out by measuring pressure or temperature of liquid coolant flowing out of each deflector coolant passage, and controlling flow of coolant through the passages such that the measured pressures or temperatures are the same.